Brown was born in London. He was educated at Haberdashers' Aske's School and the University of London where he read engineering. He trained as an engineer with ITT in London where he worked on the development of electronic systems, and the UK Atomic Weapons Research Establishment at Orford Ness and Aldermaston where he was part of the team developing monitoring systems for the international test ban treaty. He emigrated to Canada in 1963 where he worked for four years with Canadian Marconi in Montreal on the design of airborne radar and navigation systems.
In 1978 he founded with three colleagues Metier Management Systems in London, the first company to develop and market mini-computer-based systems for the management of large scale projects.
In 1999 Brown joined IHEU as a member of the Committee for Growth and Development. He became a vice-president of IHEU in 2001 and president from 2003 to 2006. Since 2004 he has been the IHEU representative at the UN Human Rights Commission (now Council) in Geneva. He chairs the IHEU Committee for Growth and Development.
In 2006, Brown received the Danish Free Press Society's Free Press Prize together with the Norwegian-Pakistani comedienne Shabana Rehman. The prize announcement stated that "Roy Brown has been a tireless advocate of free speech as part and parcel of human rights. He has thus made an invaluable contribution to the defence of the open society and freedom of expression."